Sitting for hours on end increases your risk of heart attack and stroke, even if you exercise regularly.

“Intermittent exercise doesn’t compensate for the time you sit,” says Harmony R. Reynolds, MD, associate director of the Cardiovascular Clinical Research Center at NYU Langone Medical Center, in New York City.

Why? The lack of movement may affect blood levels of fats and sugars.

Dr. Reynolds advises walking around periodically and, if you’re at work, standing up to talk on the phone.

Are you feeling stressed, hostile, or depressed? It can take a toll on your heart.

While everyone feels this way some of the time, how you handle these emotions can affect your heart health. “Those likely to internalize stress are in greater danger; research has shown a benefit to laughter and social support,” Dr. Reynolds says.

“And it’s helpful to be able to go to someone and talk about your problems.”

More than a minor annoyance, snoring can be a sign of something more serious: obstructive sleep apnea. This disorder, marked by breathing that is interrupted during sleep, can cause blood pressure to skyrocket.

More than 18 million Americans adults have sleep apnea, which increases the risk of heart disease. People who are overweight or obese are at higher risk for sleep apnea, but slim people can have it too.

If you snore and often wake up feeling tired, talk with your doctor; there are easy ways to screen for apnea, says Robert Ostfeld, MD, associate professor of clinical medicine at Montefiore Medical Center, in New York City.

“I see so many people in their 40s and 50s dive into exercising with good intentions, hurt themselves, and then stop exercising all together,” says Judith S. Hochman, MD, director of the Cardiovascular Clinical Research Center at NYU’s Langone Medical Center.

With exercise, it’s wise to aim for slow and steady. “It’s more important to have a regular exercise commitment,” says Dr. Reynolds. “Be in it for the long game.”

Dr. Reynolds and Dr. Hochman also suggest cutting portion sizes for high-calorie carbohydrates (think refined pastas and breads) and watching out for foods labeled “low-fat,” which are often high in calories.

It’s best to think of red meat as an occasional treat rather than the foundation of a daily diet. Red meat is high in saturated fat, and there’s also evidence that processed meat, such as bacon and hot dogs, increases your risk of cardiovascular disease and colorectal cancer. Ideally, less than 10% of your diet should come from animals and animal products, Dr. Ostfeld advises.

Can’t part with the beef? Choose a lean cut of red meat and limit your intake. “People have to know that if you want a steak a few times a month, it’s OK,” Dr. Hochman says. “It’s what you’re eating three times a day that’s the issue. Be in it for the long haul. Eat a balanced diet.”

Check in with an MD so that you know your numbers for cholesterol, blood pressure, and blood sugar.

If these are elevated, you’re at risk for silent killers like heart disease, stroke, and diabetes.

One thought: The lifetime risk of developing hypertension, or high blood pressure, for adults in their mid-50s is approximately 90%, even with those who never had a problem before. “The general point is that just because you didn’t have it at 24 doesn’t mean you don’t have it at 54,” Dr. Ostfeld says.

“The most heart-healthy diet is a plant-based diet,” Dr. Ostfeld says. That means loading up on fruits and vegetables, nuts, whole grains, low-fat dairy, and protein, and keeping junk food to a minimum. In fact, new federal dietary guidelines recommend that half of each meal should be composed of fruits and vegetables.

Research has found that people who eat more than five servings of fruits and vegetables a day had about 20% lower risk of heart disease and stroke than people who ate less than three servings per day.

If you used to walk up three flights of stairs without a problem, but suddenly you’re short of breath after one flight or have chest pressure, it’s time to call your doctor—now. Never assume it’s because you’re out of shape.

Doctors say “time is muscle,” meaning the quicker you get treatment for possible trouble, the less likely you are to have permanent damage to your heart muscle.

“It’s better for it to be much ado about nothing than sitting on a heart attack for six hours,” which is not uncommon, Dr. Ostfeld says.

The more salt you consume, the higher your blood pressure rises. One in three American adults has high blood pressure, a major risk factor for stroke, kidney failure, and heart attack.

“Steer clear of packaged junk food, read the labels for sodium content, and stick to the outer portions of the supermarket, which is where the fruits, vegetables, and (unsalted) nuts are,” Dr. Ostfeld says.

Most of us should keep sodium intake below 2,300 milligrams a day. If you have high blood pressure or are over 50, cut back to 1,500 milligrams.

Foods high in sugar, fat, and oil deliver calories, but very few—if any—nutrients your body can use.

Studies have shown that a diet full of empty calories increases the risk of obesity and diabetes.

Look for foods dense in nutrients, such as vegetables, fruits, whole grains, seafood, eggs, beans and peas, and unsalted nuts and seeds. Lean meats and poultry, along with fat-free and low-fat milk, are good choices as well.